Metallurgical furnace.



J. E. GRBENAWALT.

METALLURGICAL FURNACE APPLICATION FILED 001210, 1912 1,1 03,1 96, Patented July 14, 1914.

3 SHBETSSHEET 1.

H WITNESSES: INVENTOR- Lfoim E- Grzmawafi- ,"H LZ/UM/M T W K5744 A T'I'U ILVE Y,

J. E. GRBENAWALT. METALLURGICAL FURNACE.

APPLICATION FILED DOT. 1O 1912.

1,103, 1 96. Patented July 14,191

3 SHEETS-SHEET 2.

WITNESSES: IN VENTOR.

6 Q [Io/m E-Greenawalt- A TIIORNE Y.

J. E. GRBENAWALT. METALLURGIGAL FURNACE.

APPLICATION FILED 0OT.I0,1912.

1, 103,1 96. Patented July 14, 1914.

3 SHEETS SHBET 3.

, B Y W MQMQ JOHN E. GREENAWALT, 01 DENVER, COLORADO.

METALLURGICAL FURNACE.

Specification of Letters Patent.

Patented July 14, 1914.

Application filed October 10, 1912. Serial No. 725,032.

To all w]: 0722- it may concern:

Be it known that I, JOHN E. GREENAWALT, citizen of the United States, residing at Denver, in the county of Denver and State of Colorado, have invented certain new and useful Improvements in Metallurgical Fur- ,naces, of which the following is a full, clear, and exact description. reference being bad to the accompanying drawings, forming a part hereof.

My invention has relation to improvements in metallurgical furnaces; and it consists in the novel features of construction more fully set forth in the specification and pointed out in the claims.

In the drawings. Figure 1 is a vertical cross-section of the main form of my furnace on the line l1 of Fig. 2, with parts in elevation; Fig. 2 is a vertical longitudinal section on the line 2-2 of Fig. 1, with parts in elevation: Fig. 3 is a side elevation of a series of two furnaces shown] a single upper section available for use with either of two bottom sections: Fig. 4 is a side elevation of a furnace showing a modified. form of bottom section; and Fig. 5 is a vertical cross-section on the line 55 of Fig. 4.

The present'invention is an improvement on the general type of furnace forming the subject-Hunter of U. S. Letters Patent issued to me under date of December 18, 1906, numbered 839.064. and has for its object to so modify the patented construction as to permit access to the entire charge of the furnace at one time. this being desirable in furnaces having a restricted hearth area, and whose capacity corresponds to the contents of a preferably single charge-car. n such cases it is desirable that the contents of the car (or cars) be dumped on the hearth of the furnace. the material being afterward leveled off to an even thickness over the hearth to insure uniform treatment thereof. Where the charge is of such character as not to call for or neccssitate the recovery of values of precious metals (one of the objects contemplated by my patent aforesaid) as for errample where mere roasting or sintering is the object sought, it is economical to apply the downdraft principle or method of oxidation covered by said patent. on relatively small charges, thus permitting the use of comparatively small furnaces the product of which can be conveniently handled because readily accessible. To secure such ready acoess to the material treated (oxidized, roasted. or sintered) I construct a downdraft porous hearth furnace in two sections separable along a horizontal plane disposed pref erably even with. or just above, the plane of the upper surface of the charge resting on the porous hearth. the lower section containing the hearth or bed and its perforated support. and the upper section forming with the lower section a gas or roasting chamber above the charge. Into this chamber air and ignition fuel (as fully described in my patcnt aforesaid) are introduced to furnish the heat and oxygen to the charge for purposes of roasting and oxidation, my present improvement possessing the advantage that in cases where the charge inherently contains suflicient combustible constituents (carbon, sulfur and the like) to supply the fuel to generate the necessary roasting or sintering heat. a single upper furnace-section may be used successively with the lower sections of a number of furnaces. This flows from the fact that once the fuel contents of a charge resting on the hearth is ignited by the air and burning gases in the chamber above the charge. (the ignition being obviously at the surface of the charge) the upper section may be removed and deposited over a corresponding lower section of another and similar furnace, the air drafted through the charge in the furnace from which the upper section was removed permeating the charge. whereby the combustion of the fuel contents thus ignited continues through the charge down to its support, by which time the material has become thoroughly treated or oxidized (roasted or sinter-roasted as the case may be). The removal of the upper furnace-section from the lower section exposes the latter. making the hearth and the material deposited thereon readily accessible. thereby rendering it convenient to quickly charge the furnace or remove the roasted material therefrom. In char ing one furnace, the removed upper comp ementary section may be deposited over the bottom section of another similar furnace, and left in position thereon long enough to insure the necessary treatment of the charge in said furnace, depending on the character of the charge treated and on the quantity of available combustible constituents or fuel contents of said charge. The sectional character of my furnace too, permits the same to be charged (or discharged) by the removal or mere lifting of the upper section, a dei of ribs r whereby a chamber (1 cided advantage where economy of time is a desideratum.

The various advantages of the invention will be best apparent from a detailed description thereof, which is as follows z-Refer-ring to the drawings, and for the present to Figs, 1 to 3 inclusive, W represents the setting of brick work or cement on which my furnace is supported, the walls W forming between th housing of a suitable electric motor M which drives the exhaust fan or exhauster E by which the air and gases are drafted downward through the charge and its support, the exhauster being coupled to the bottom section 1 of the furnace by means of a pipe I. In the present embodiment of my invention the bottom furnace-section is prefcrably made of iron and provided with an upper marginal flange a on which the upper sect ion 2 is deposited when lowered in position. The bottom section is of sufficient depth to receive suitable grate bars (l spaced from the bottom of said section by means for the gases drawn through the charge is formed, the pipe 1 being in immediate communication with said chamber. The grates collectively form a perforated support for the layer or bed It forming the porous hearth for the charge m, said grates being herein substituted for the bricks H described in my patent aforesaid and answering a like purpose. The layer h constituting the porous bed for the charge may be of any suitable non-comlmstible relatively coarse, porous material such as gravel and the like not liable to adhere to the grates under the temperature to which the charge may be subjected. The space above the bed h will accommodate a layer of ore or equivalent charge m of about a foot in thickness, the surface of the charge being leveled off substantially in a plane even with the faces of the flanges a. The bottom furnace-section thus charged is ready to receive or have deposited thereover the upper removable section 2. This section (2) may be suspended by cables 3 secured respectively to eyes 4 formed in the reinforcing arched Tbars 5 which enter into the construction of the upper section, and to a hoisting and lowering cable 6 passing over pulleys 7, 8, the outer end of the cable 6 being provided with a counterweight 9. When the section 2 is raised, the bottom section with its hearth (and grates G) is left exposed and made accessible, and may be charged from a charge-car 10 running on a track T alongside the furnace, the contents of a single car generally sufiicing to constitute a full charge. The charge being leveled s aforesaid, the section 2 is deposited on the flanges a of the section 1, the contacting surfaces between the sections makmg an air tight joint or seal, and thus preem a chamber for the y venting the influx of lateral air torrents across the surface of the charge-an objection not desirable as it interferes with the even distribution of the burner gases over the charge within the gas or roasting chamber R formed by the upper section 2 with the surface of the charge. The roof of the upper section 2 is provided with air intake openings 0 which supply the necessary complement. of oxyge to the gas (or equivalent) fuel admitted into the chamber R from the nozzles ll leading from the valvecontrolled pipe 12 and. communicating with said chamber through the end wall of the section 2. Since in the present embodiment of my invention the upper section is separable or removable from the bottom secl tion, it becomes desirable to attach to the pipe 12 a flexible hose 13 leading to any suitable source of gas or equivalent fuel supply (not shown).

In my patent aforesaid (839,064) it will be noted that the ignition fuel is introduced into the roasting chamber through a flue 2 i the roof thereof, such an arrangement not being desirable in the treatment of the relatively small charges contemplated by my present furnace. In the improvement herein the ignition fuel is introduced preferably through the end Walls of the upper section, so as to get close as possible to the surface of the charge, which surface is disposed substantially along the plane of separation be tween th two sections of the furnace. The ignition fuel or burner gases being thus introduced through a vertical wall of the upper section, it is obvious that to secure for such gases the even distribution thereof over the surface of the charge, they must be directed into the roasting chamber substantially parallel to said surface and substantially at right angles to said wall, as fully shown in the drawings (Fig. 2). The present furnace is further characterized by the absence of any burners in the roasting chamber, and of any burners directing the gases against the surface of the charge, which is always objectionable where treating the charge by a d wndraft, since the downdraft draws a large portion of such burner gases into the body of the charge before they have a chance to distribute themselves over the surface of the charge or to flash into flame for the purpose of igniting said surface.

he operation, which is substantially the same as in my patent aforesaid may be briefly summarized as follows :--Assuming that the furnace has been charged and the two sections assembled as aforesaid, the valve V at the pipe 12 is turned on so as to admit the igniting fuel, the latter being lighted by means of a torch inserted for example through one of the air openings 0 (or through a special torch opening placed where most convenient, not here shown).

At the same time the motor M is started to operate the exhauster E which has the effect 0 drawing the roaster gases, air, and gases of combustion through the charge and its support (porous hearth and grates), into the chamber C below the grates, and out of said chamber through the pipe P as quite obvious from the drawings. The air drawn through the openings 0 not only serves to furnish the necessary complement of oxygen for the combustion of the fuel projected into the chamber R from the nozzles 11, but furnishes the required oxygen for the oxidation of the combustible constituents of the charge, roasting or sinter-roasting contemplating oxidation (as well understood in the art) in contradistinction to calcination or distillation which merely contemplates expulsion of some volatile constituent. Should such latter treatment be desired in my furnace this may be done by closing a portion of the openings 0 so that only sufficient air shall be admitted to consume the fuel introduced through the nozzles 11, the temperature of combustion of such fuel furnishing the necessary heat to treat the material on the hearth.

Where the charge carries suflicient combustible constituents to furnish fuel to generate its own heat, the extraneous fuel introduced into the chamber R through the nozzles 11 may be cut off, once the fuel in the charge has become ignited (such ignition obviously taking place at the surface of the charge), and air only may be admitted through the openings 0, the air enteringthe chamber R and thence being drafted by the exhauster through the charge thus ignited, the zone of combustion continuing until the bottom of the charge is reached when the charge will be fully roasted or sinter-roasted as the case may be. The charge being fully treated, the operator lifts off the upper furnace-section thus gaining access to the entire charge at one time. The roasted chare may then be removed from the grates G, a portion of the layer h usually adhering to the charge, which is no objection as the mass broken into suitable lumps is subsequently treated in a blast or equivalent reducing furnace, in which the adhering particles enter as components of the flux or slag) in any suitable manner obvious to the skilled mechanicl The furnace being composed of two sections, it is obvious that where a charge is treated which has sufficient fuel contents to generate its own heat (requiring no extraneous heat after the period of ignition) the upper section instead of being allowed to remain on the bottom section may be removed and deposited over a bottom section of another similar furnace where a charge is to be treated, thus making the upper section available for a number of bottom sections. The charge in the bottom section from which the upper section has thus been removed will continue to roast or oxidize from topdownward under the action of the exhauster which continues to draft the air through the charge thus exposed, the velocity of penetration of the air and the rate of progression of the zone of combustion being carefully regulated by a proper regulation of the speed of the motor M. To permit the transfer of a single top section 2 from the bottom section of one furnace to the corresponding bottom section of another furnace, the pulleys 7, 8, may be attached to a carriage or frame D which is provided with rollers 14, 14, traveling between rails forming a track 15, the frame being provided with cables 16 by which it may be drawn in either direction. In Fig. 3 I have shown the top section 2 of one furnace, removed and deposited over the bottom section 1 of another furnace. The several bottom furnace-sections may be charged by the same car 10, the track T passing alongside all the sections (two sections being here shown). The lower section may be dumped by turnin the same on its axis (the upper section icing removed), this being made possible by providing the same with trunnions 20, 20', one of which (20), is hollow. In that event the trunnion 20 discharges the gases into a box 21 from which the pipe P leads to the exhauster. The hollow trunnion feature per se is not claimed herein, being a well known expedient in Bessemer steel converters. A bottom section so mounted is shown as a modification in Figs. 4 and 5.

As pointed out above, the inflammable material or ignition fuel is introduced into the roasting chamber at points disposed along the walls of the furnace, contiguous to the sealing plane or plane of separation between the furnace-sections; and in the furnace herein illustrated, the nozzles are preferably on the walls of the upper section.

do not however, wish to be understood that the location of the nozzles or their equivalents must in all cases be on the upper section, it being within the scope of my invention to locate them if necessary or desirable, on the walls of the bottom section, provided they are positioned contiguous to the sealing plane between the sections and discharge above the surface of the charge deposited in the bottom section. It follows therefore, that the nozzles though contiguous to the sealing plane, may be either above said plane or below it; in the furnace here shown they are above it.

The present invention need not of course, be restricted in its application to metallurgical furnaces.

Features shown but not alluded to are well understood in the art and no description thereof is here necessary.

In order to have the two sections of the furnace separable one from the other, it is perfectly obvious that the up or section may be the stationary one, and t at the bottom section may be moved up to, and away from the upper section. Accordingly, I do not wish to confine myself to a construction which contemplates a fixed lower section and a movable upper section, it being within the contemplation and spirit of my invention to have the upper section fixed or stationary and the lower section movable. This reversal of construction comes within the skill of the ordinary mechanic and requires no illustration.

Having described my invention, claim is z 1. A metallurgical furnace comprising a bottom section provided with a perforated support for the charge, an upper removable section engagin the bottom section, and forming a scale chamber therewith above the charge upon the assembling of the sections, means for introducing a supporter of combustion into said chamber through the walls of the upper section, and means on the walls of the upper section located at points contiguous to the seal between the sections and above the sealing plane for introducing inflammable material into said chamber.

2. A metallurgical furnace comprising a bottom section provided with a perforated support for the charge, an upper removable section engaging the bottom section and forming a sealed chamber therewith above the charge upon the assembling of the sections, means for introducin a supporter of combustion into said cham or through the walls of the upper section, and means on the walls of the furnace located at points contiguous to the seal between the sections and operating into the chamber in paths substantially parallel to the surface of the charge.

3. A metallurgical furnace comprising a bottom section rovided with a perforated support for the charge, an upper removable section engaging the bottom section and forming a sealed chamber therewith above the charge upon the assembling of the sections, means on the upper section for admitting air into said chamber, an exhauster coupled to the bottom section, and means disposed on the walls of the furnace at points contiguous to the seal between the sections, for introducing inflammable material into the furnace chamber above the surface of the charge.

4. A metallurgical furnace comprising a bottom section provided with a perforated support for the charge, and an upper removable section engaging the bottom section and forming therewith a chamber above the charge sealed along the plane of separation between the sections, means on the upper what I to introduce inflammable material section for permitting an influx of atmospheric air into said chamber, means on the upper section positioned above the surface of the charge for introducing inflammable material into said chamber in paths substantially parallel to said surface, and means coupled to the bottom section for drafting the air and gases through the charge and its support.

A metallurgical furnace comprising a bottom section provided with a perforated support for the charge, and an upper removable section engaging the bottom section and forming therewith a chamber above the charge sealed along the plane of separation between the secti ns. means on the upper section for permitting an influx of atmospheric air into said chamber, means for introducingin paths substantially in parallel to the surface of the charge inflammable material into said chamber from points contiguous to the scaling plane between the sections. and means coupled to the bottom section for drafting the air and gases through the charge and its support.

6. A metallurgical furnace comprising a bottom section provided with a perforated support for the charge, an upper removable section engaging the bottom section and forn'ling a sealed chamber therewith above the charge upon the assembling of the sections, means for introducing a supporter of combustion into said chamber, an exhauster coupled to the bottom section, and means disposed on the walls of the furnace at points contiguous to the seal between the sections, for introducing inflammable material into the furnace chamber above the surface of the charge.

7. A metallurgical furnace comprising a bottom section adapted to support the charge, an upper removable section engaging the ho tom section and forming therewith a sea. d chamber above the charge upon the assembling of the sections, means disposed on the walls of one of the sections at points contiguous to the seal between the sections. for introducing inflammable ma terial into the furnace chamber above the surface of the charge, and suitable means for the escape of the gases and combustion products from said chamber.

8. A metallurgical furnace comprising a bottom section for the support of the char 'e, an upper removable section engaging tic bottom section and forming therewith a sealed chamber above the charge upon the assembling of the sections, means for introducing a supporter ,of combustion into the chamber, means disposed on the walls of one of the sections at points contiguous to the seal between the sections, for intro ducing inflammable material into the chamber above the charge, and means providing an escape for the gases and combustion products through the charge and through the bottom section.

9. A metallurgical furnace consisting of a lower section having a perforated support for the charge, a removable cover section engaging the lower section, and forming therewith a sealed chamber above the charge when so engaged, an exhauster coupled to the lower section, and means disposed on the walls of the furnace at points contiguous to the seal between the sections, for intro ducing inflammable material into the furnace chamber above the surface of the charge.

10. A metallurgical furnace consisting of a lower section having a perforated support for the charge, a removable cover section engaging the lower section, and forming therewith a sealed chamber above the charge when so engaged, an exhauster coupled to the lower section, and means disposed on the Walls of the furnace at points contiguous to the seal between the sections, for introducing into the furnace chamber above the surface of the charge, inflammable material in the presence of a supporter of combustion.

In testimon whereof I afiix my signature in presence o two witnesses.

JOHN E. GREEN AWALT.

Witnesses:

GEORGE F. PIGKEN, C. L LINDELOF.

Correction in Letters Patent No. 1,103,196,

an escape for the gases and combustion products through the charge and through the bottom section.

9. .A metallurgical furnace consisting of a lower section having a perforated support for the charge, a removable cover section engaging the lower. section, and forming therewith a, sealed chamber above the charge when so engaged, an exhauster coupled to the lower section, and means disposed on the walls of the furnace at points contiguous to the seal between the sections, for introducing inflammable material into the furnace chamber above the surface of the charge.

10. A metallurgical furnace consisting of a lower section having a .perforated support case in the Patent Oflice.

[SEAL] 1914, upon the application of John E. Greenawalt, of Denver, Colorado,

improvement in Metallurgical Furnaces,

for the'charge, a removable cover section JOHN E. GREENAWALT. I

Witnesses:

GEORGE F. PIoKEN, C. L LINDELOF.

It is hereby certified that in Letters Patent No, 1,103,196, granted July 14,

for an an error appears in the printed specification requiring correction as follows: Page 4, 'line 83, after the Word substantially strike out the word in; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the Signed and sealed this 22nd day of September, A. D. 1914.

R. F. WHITEHEAD,

Aching fPatents.

It is hereby certified that in Letters Patent No. 1,103,196, granted July 14,

1914, upon the application of John E. Greenawalt, of Denver, Colorado, for an improvement in Metallurgical Furnaces, an error appears in the printed specification requiring correction as follows: Page 4, line 83, after the word substantially strike out the word in; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of September, A. D., 1914.

[emu] R. F. WHITEHEAD,

Acting Omnmisaimer qfPatenta. 

